Gearbox actuators of the general type under consideration are used to automate gearboxes in manual transmissions. In such manual transmissions, it is proposed that a gear selector element, which would be operated with a gear stick on manual operation, is guided along a selection gate to a desired shift gate and then moved into a gear position in order to engage a gear. Usually several shift gates are provided along the selection gate, transverse to the selection gate. These shift gates end in positions in which a gear is engaged. FIG. 1 is a high level schematic showing, as an example, a gearbox with six forward gears and one reverse gear. Three shift gates 9, 10, 11 are provided along a selection gate 7 for forward gears and a further shift gate 8 for reverse gear.
A gearbox actuator for gearbox automation usually has an actuating cylinder via which the gear selector element is guided along the selection gate and can be positioned at an intersection point of a desired shift gate. Such an actuating cylinder is called a gate selection actuating cylinder. To engage a gear in the selected shift gate, a gear selection actuating cylinder is provided that guides the gear selection element accordingly into the selected shift gate and positions it so that the desired gear is engaged.
For precise positioning of the gear selection element in the selection gate, conventional gearbox actuators use a gate selection actuating cylinder with a number of defined shift positions corresponding to the number of shift gates, which positions can be set by activation of a pressure medium. To approach three positions, for example, a three-position cylinder is used. Such a three-position cylinder is in itself already relatively complex. For precise positioning with a higher number of shift positions, the design complexity for a corresponding multiposition cylinder would be even greater.